No, you can only install pure Python modules yourself. Modules such as numpy and matplotlib that use C, Cython, Fortran or other compiled languages need to be integrated into Pythonista by omz, because Apple's app guidelines do not allow compiling native code in an app, and simply because there are no C compilers for iOS on iOS.
This is the community forum for my apps Pythonista and Editorial.
For individual support questions, you can also send an email. If you have a very short question or just want to say hello — I'm @olemoritz on Twitter.